1. Technical Field
The following description relates to a display device, and more particularly, to a display device with an input system.
2. Discussion of the Related Art
Various kinds of input devices may be used for electronic systems, for example, computers such as a laptop computer, a tablet computer, and a personal digital computer; and communication devices such as a mobile phone, and a handheld communication device.
Among the various kinds of input devices, a capacitive touch panel is used widely, which is an input device capable of determining a location of touch by sensing a change of capacitance between a contact surface of the input device and a part of human body being in contact with the input device, for example, a finger or palm.
Also, there is another input device of a digitizer or a tablet PC, which determines a location of touch through the use of indicator, for example, imaging device such as stylus or pen-shaped object.
Generally, in comparison to the capacitive touch panel, the digitizer has better precision in detecting a location of touch, and greater resolution, however, the digitizer is disadvantageous in that it inevitably requires an indicator (for example, stylus or other pen). Thus, there has been a strong desire to combine the advantages of capacitive touch panel (for example, convenience) with the good precision and resolution of the digitizer.
Hereinafter, a display device with an input system, which is capable of using the finger and pen according to the related art, will be described with reference to FIG. 1.
FIG. 1 illustrates problems that may occur in a display device with an input system according to the related art. In particular, FIG. 1 illustrates problems that may occur in a capacitive touch sensing panel and an electromagnetic touch sensing panel.
As shown in FIG. 1, the display device with an input system according to the related art includes a capacitive touch panel 10 and an electromagnetic touch panel 20.
For touch sensing using the capacitive touch panel 10, a change of capacitance is measured by comparing a capacitance after touching the device with a capacitance before touching the device, to thereby determine whether or not the display device is touched, and determine the coordinates of a touched portion. When measuring the change of capacitance in the coordinates of the touched portion of the capacitive touch panel 10 provided with a plurality of sensing electrodes, the capacitive touch panel 10 is exposed to display noise for a considerable period of time, which might cause deterioration in the touch function.
For touch sensing using the electromagnetic touch panel 20, an induced current flows in the electromagnetic touch panel 20 through the use of a pointing device such as stylus or pen, to thereby determine whether or not the display device is touched, and determine the coordinates of a touched portion. If the electromagnetic touch sensing is performed for a period of the capacitive touch sensing, noise caused by the pointing device, such as a stylus or pen, may flow toward the capacitive touch panel 10, whereby a malfunction may occur in the capacitive touch sensing.
Although not shown in FIG. 1, both drivers for driving the capacitive touch panel 10 and electromagnetic touch panel 20 may be simultaneously driven in the display device with an input system according to the related art, whereby power consumption may be increased.
Therefore, the display device with an input system according to the related art has the following disadvantages.
If the electromagnetic touch sensing is performed for the period of capacitive touch sensing, noise occurring in the electromagnetic touch panel 20 may flow toward the capacitive touch panel 10, whereby a malfunction may occur in the capacitive touch sensing.
Also, both drivers for driving the capacitive touch panel 10 and electromagnetic touch panel 20 may be simultaneously driven in the display device with an input system according to the related art, whereby power consumption may be increased.